High-low-voltage (HLV) lighting fixtures may include an end plate that is attached to a mid-cap at one or both longitudinal ends of the lighting fixtures. The seam that exists between the end plate and the mid-cap is generally noticeable and can result in an unappealing aesthetic appearance. In some cases, many screws are used to secure the end plate to the mid-cap and to secure the mid-cap to one or more extrusion frames of a lighting fixture. The relatively large number of screws and other parts can make assembly/installation a time consuming and expensive process. Further, a multiunit HLV lighting fixture may require a joiner cap that is positioned between adjacent mid-caps for attachment of the individual lighting fixture units to each other to form the multiunit lighting fixture. Thus, a single unit end cap that can be coupled to extrusion frames of an HLV lighting fixture without use of a mid-cap and a relatively small number of fasteners may reduce assembly/installation time and cost while providing an improved aesthetic appearance. Further, single-piece end caps that can be coupled together without use of a joiner cap in the assembly/installation of multiunit HLV lighting fixtures may also reduce assembly/installation time and cost while providing improved an aesthetic appearance.